[dv/mem_bkdr_if] inject parity errors
this PR adds support to the mem_bkdr_if for parity error injection.
this is done by flipping a single bit in the byte data and backdoor
writing this corrupted data after calculating the parity based off of
the uncorrupted data value.
note that parity error injection will only work if the `MEM_PARITY`
parameter is enabled.
Signed-off-by: Udi Jonnalagadda <udij@google.com>
diff --git a/hw/dv/sv/mem_bkdr_if/mem_bkdr_if.sv b/hw/dv/sv/mem_bkdr_if/mem_bkdr_if.sv
index 83fe006..daddbc7 100644
--- a/hw/dv/sv/mem_bkdr_if/mem_bkdr_if.sv
+++ b/hw/dv/sv/mem_bkdr_if/mem_bkdr_if.sv
@@ -20,6 +20,9 @@
// The `MEM_PARITY` parameter is used to indicate whether the target memory uses parity checks.
// If so, we need to take care to modify the read/write indices, as the total memory width will be
// `mem_bytes_per_word * 8 + mem_bytes_per_word` as we have one parity bit per data byte.
+// Enabling this parameter also allows access to parity error injection functionality - to use this
+// all that needs to be done is to set the `inject_parity_err` argument in any of the backdoor write
+// functions.
//
// The `MEM_ECC` parameter is used to indicate whether the target memory uses an ECC implementation,
// so we can ensure to usethe proper data encoding scheme.
@@ -153,10 +156,18 @@
return 'x;
endfunction
- function automatic void write8(input bit [bus_params_pkg::BUS_AW-1:0] addr, input bit [7:0] data);
+ function automatic void write8(input bit [bus_params_pkg::BUS_AW-1:0] addr,
+ input bit [7:0] data,
+ input bit inject_parity_err = 0);
if (is_addr_valid(addr)) begin
int mem_index = addr >> mem_addr_lsb;
bit [MAX_MEM_WIDTH-1:0] rw_data = `MEM_ARR_PATH_SLICE[mem_index];
+
+ // Prepare corrupted data if a parity error injection is requested
+ bit [2:0] idx_to_corrupt = $urandom_range(0, 7);
+ bit [7:0] corrupted_data = data;
+ corrupted_data[idx_to_corrupt] = !corrupted_data[idx_to_corrupt];
+
// Note that if memory parity checks are enabled,
// we have to write the correct parity bit as well.
// Odd parity is used, rather than even parity checking.
@@ -167,24 +178,36 @@
rw_data[0 +: 8] = data;
if (MEM_PARITY) begin
rw_data[0 + 8] = ~(^data);
+ if (inject_parity_err) begin
+ rw_data[0 +: 8] = corrupted_data;
+ end
end
end
2: begin
rw_data[addr[0] * MEM_BYTE_MSB +: 8] = data;
if (MEM_PARITY) begin
rw_data[addr[0] * MEM_BYTE_MSB + 8] = ~(^data);
+ if (inject_parity_err) begin
+ rw_data[addr[0] * MEM_BYTE_MSB +: 8] = corrupted_data;
+ end
end
end
4: begin
rw_data[addr[1:0] * MEM_BYTE_MSB +: 8] = data;
if (MEM_PARITY) begin
rw_data[addr[1:0] * MEM_BYTE_MSB + 8] = ~(^data);
+ if (inject_parity_err) begin
+ rw_data[addr[1:0] * MEM_BYTE_MSB +: 8] = corrupted_data;
+ end
end
end
8: begin
rw_data[addr[2:0] * MEM_BYTE_MSB +: 8] = data;
if (MEM_PARITY) begin
rw_data[addr[2:0] * MEM_BYTE_MSB + 8] = ~(^data);
+ if (inject_parity_err) begin
+ rw_data[addr[2:0] * MEM_BYTE_MSB +: 8] = corrupted_data;
+ end
end
end
default: ;
@@ -194,28 +217,37 @@
endfunction
function automatic void write16(input bit [bus_params_pkg::BUS_AW-1:0] addr,
- input bit [15:0] data);
+ input bit [15:0] data,
+ input bit inject_parity_err = 0);
+ // ensure that parity errors are only injected into one sub-byte write
+ bit inject_parity_err_in_first_sub_write = $urandom_range(0, 1);
`DV_CHECK_EQ_FATAL(addr[0], '0, $sformatf("addr 0x%0h not 16-bit aligned", addr), path)
if (is_addr_valid(addr)) begin
- write8(addr, data[7:0]);
- write8(addr + 1, data[15:8]);
+ write8(addr, data[7:0], inject_parity_err_in_first_sub_write && inject_parity_err);
+ write8(addr + 1, data[15:8], !inject_parity_err_in_first_sub_write && inject_parity_err);
end
endfunction
function automatic void write32(input bit [bus_params_pkg::BUS_AW-1:0] addr,
- input bit [31:0] data);
+ input bit [31:0] data,
+ input bit inject_parity_err = 0);
+ // ensure that parity errors are only injected into one sub-byte write
+ bit inject_parity_err_in_first_sub_write = $urandom_range(0, 1);
`DV_CHECK_EQ_FATAL(addr[1:0], '0, $sformatf("addr 0x%0h not 32-bit aligned", addr), path)
if (is_addr_valid(addr)) begin
- write16(addr, data[15:0]);
- write16(addr + 2, data[31:16]);
+ write16(addr, data[15:0], inject_parity_err_in_first_sub_write && inject_parity_err);
+ write16(addr + 2, data[31:16], !inject_parity_err_in_first_sub_write && inject_parity_err);
end
endfunction
function automatic void write64(input bit [bus_params_pkg::BUS_AW-1:0] addr,
- input bit [63:0] data);
+ input bit [63:0] data,
+ input bit inject_parity_err = 0);
+ // ensure that parity errors are only injected into one sub-byte write
+ bit inject_parity_err_in_first_sub_write = $urandom_range(0, 1);
`DV_CHECK_EQ_FATAL(addr[2:0], '0, $sformatf("addr 0x%0h not 64-bit aligned", addr), path)
- write32(addr, data[31:0]);
- write32(addr + 4, data[63:32]);
+ write32(addr, data[31:0], inject_parity_err_in_first_sub_write && inject_parity_err);
+ write32(addr + 4, data[63:32], !inject_parity_err_in_first_sub_write && inject_parity_err);
endfunction
///////////////////////////////////////////////////////////
